1. Field of the Invention
The present invention is generally in the field of semiconductor device packaging. More specifically, the invention is in the field of shielding of semiconductor device packages.
2. Related Art
Portable electronic devices, such as cell phones, typically utilize multi-component semiconductor modules to provide a high level of circuit integration in a single molded package. The multi-component semiconductor module can include, for example, a semiconductor die and a number of electronic components, which are mounted on a circuit board. The circuit board including the semiconductor die and electronic components can be encapsulated in a molding process to form an overmolded semiconductor package. To ensure an acceptable level of performance in devices such as cell phones, which are required to properly operate in diverse environments, the overmolded semiconductor package must be shielded from Electro-Magnetic Interference (EMI) and/or Radio Frequency Interference (RFI). However, semiconductor device manufacturers are challenged to provide effective EMI and RFI shielding for an overmolded semiconductor package without increasing the size of the package and without substantially increasing packaging cost.
In one approach, EMI and RFI shielding is provided by forming a discrete metal shield over the overmolded semiconductor package. The metal shield typically includes a wall, which is formed around the overmolded semiconductor package, and a cover, which is attached to the wall and situated a sufficient distance above the overmolded package to avoid interfering with the package. As a result, the metal shield undesirably increases the thickness of the final overmolded package. Also, the formation of the metal shield requires an extra process step and additional materials, which significantly increases packaging cost.
In another approach, conductive foam or rubber is applied over the overmolded semiconductor package to absorb and trap EMI. However, the conductive foam or rubber must be applied manually and requires special materials and an extra process, which significantly increases packaging cost. Additionally, the conductive foam or rubber undesirably increases the thickness of the final overmolded package.
Thus, there is a need in the art for a cost-effective EMI and RFI shield for an overmolded semiconductor package that does not substantially increase package thickness.